Refactoring to support parameterized queries.

This commit is contained in:
zer0sub 2019-04-29 14:39:48 +02:00
parent bc6a2bbcac
commit fef8f0ef83
33 changed files with 1112 additions and 1206 deletions

View file

@ -1,17 +1,9 @@
package sqlbuilder
import (
"bytes"
"database/sql"
"fmt"
"github.com/dropbox/godropbox/errors"
"github.com/sub0zero/go-sqlbuilder/types"
)
// By default, rows selected by a UNION statement are out-of-order
// By default, rows selected by a UNION statement are out-of-orderBy
// If you have an ORDER BY on an inner SELECT statement, the only thing
// it affects is the LIMIT clause on that inner statement (the ordering will
// still be out-of-order).
// still be out-of-orderBy).
type UnionStatement interface {
Statement
@ -27,177 +19,178 @@ type UnionStatement interface {
Offset(offset int64) UnionStatement
}
func Union(selects ...SelectStatement) UnionStatement {
return &unionStatementImpl{
selects: selects,
limit: -1,
offset: -1,
unique: true,
}
}
func UnionAll(selects ...SelectStatement) UnionStatement {
return &unionStatementImpl{
selects: selects,
limit: -1,
offset: -1,
unique: false,
}
}
// Similar to selectStatementImpl, but less complete
type unionStatementImpl struct {
selects []SelectStatement
where BoolExpression
group *listClause
order *listClause
limit, offset int64
// True if results of the union should be deduped.
unique bool
}
func (s *unionStatementImpl) Query(db types.Db, destination interface{}) error {
return Query(s, db, destination)
}
func (u *unionStatementImpl) Execute(db types.Db) (res sql.Result, err error) {
return Execute(u, db)
}
func (us *unionStatementImpl) Where(expression BoolExpression) UnionStatement {
us.where = expression
return us
}
// Further filter the query, instead of replacing the filter
func (us *unionStatementImpl) AndWhere(expression BoolExpression) UnionStatement {
if us.where == nil {
return us.Where(expression)
}
us.where = And(us.where, expression)
return us
}
func (us *unionStatementImpl) GroupBy(
expressions ...Expression) UnionStatement {
us.group = &listClause{
clauses: make([]Clause, len(expressions), len(expressions)),
includeParentheses: false,
}
for i, e := range expressions {
us.group.clauses[i] = e
}
return us
}
func (us *unionStatementImpl) OrderBy(
clauses ...OrderByClause) UnionStatement {
us.order = newOrderByListClause(clauses...)
return us
}
func (us *unionStatementImpl) Limit(limit int64) UnionStatement {
us.limit = limit
return us
}
func (us *unionStatementImpl) Offset(offset int64) UnionStatement {
us.offset = offset
return us
}
func (us *unionStatementImpl) String() (sql string, err error) {
if len(us.selects) == 0 {
return "", errors.Newf("Union statement must have at least one SELECT")
}
if len(us.selects) == 1 {
return us.selects[0].String()
}
// Union statements in MySQL require that the same number of columns in each subquery
var projections []Projection
for _, statement := range us.selects {
// do a type assertion to get at the underlying struct
statementImpl, ok := statement.(*selectStatementImpl)
if !ok {
return "", errors.Newf(
"Expected inner select statement to be of type " +
"selectStatementImpl")
}
// check that for limit for statements with order by clauses
if statementImpl.order != nil && statementImpl.limit < 0 {
return "", errors.Newf(
"All inner selects in Union statement must have LIMIT if " +
"they have ORDER BY")
}
// check number of projections
if projections == nil {
projections = statementImpl.projections
} else {
if len(projections) != len(statementImpl.projections) {
return "", errors.Newf(
"All inner selects in Union statement must select the " +
"same number of columns. For sanity, you probably " +
"want to select the same tableName columns in the same " +
"order. If you are selecting on multiple tables, " +
"use Null to pad to the right number of fields.")
}
}
}
buf := new(bytes.Buffer)
for i, statement := range us.selects {
if i != 0 {
if us.unique {
_, _ = buf.WriteString(" UNION ")
} else {
_, _ = buf.WriteString(" UNION ALL ")
}
}
_, _ = buf.WriteString("(")
selectSql, err := statement.String()
if err != nil {
return "", err
}
_, _ = buf.WriteString(selectSql)
_, _ = buf.WriteString(")")
}
if us.where != nil {
_, _ = buf.WriteString(" WHERE ")
if err = us.where.SerializeSql(buf); err != nil {
return
}
}
if us.group != nil {
_, _ = buf.WriteString(" GROUP BY ")
if err = us.group.SerializeSql(buf); err != nil {
return
}
}
if us.order != nil {
_, _ = buf.WriteString(" ORDER BY ")
if err = us.order.SerializeSql(buf); err != nil {
return
}
}
if us.limit >= 0 {
if us.offset >= 0 {
_, _ = buf.WriteString(
fmt.Sprintf(" LIMIT %d, %d", us.offset, us.limit))
} else {
_, _ = buf.WriteString(fmt.Sprintf(" LIMIT %d", us.limit))
}
}
return buf.String(), nil
}
//
//func Union(selects ...SelectStatement) UnionStatement {
// return &unionStatementImpl{
// selects: selects,
// limit: -1,
// offset: -1,
// unique: true,
// }
//}
//
//func UnionAll(selects ...SelectStatement) UnionStatement {
// return &unionStatementImpl{
// selects: selects,
// limit: -1,
// offset: -1,
// unique: false,
// }
//}
//
//// Similar to selectStatementImpl, but less complete
//type unionStatementImpl struct {
// selects []SelectStatement
// where BoolExpression
// group *listClause
// order *listClause
// limit, offset int64
// // True if results of the union should be deduped.
// unique bool
//}
//
//func (s *unionStatementImpl) Query(db types.Db, destination interface{}) error {
// return Query(s, db, destination)
//}
//
//func (u *unionStatementImpl) Execute(db types.Db) (res sql.Result, err error) {
// return Execute(u, db)
//}
//
//func (us *unionStatementImpl) Where(expression BoolExpression) UnionStatement {
// us.where = expression
// return us
//}
//
//// Further filter the query, instead of replacing the filter
//func (us *unionStatementImpl) AndWhere(expression BoolExpression) UnionStatement {
// if us.where == nil {
// return us.Where(expression)
// }
// us.where = And(us.where, expression)
// return us
//}
//
//func (us *unionStatementImpl) GroupBy(
// expressions ...Expression) UnionStatement {
//
// us.group = &listClause{
// clauses: make([]Clause, len(expressions), len(expressions)),
// includeParentheses: false,
// }
//
// for i, e := range expressions {
// us.group.clauses[i] = e
// }
// return us
//}
//
//func (us *unionStatementImpl) OrderBy(
// clauses ...OrderByClause) UnionStatement {
//
// us.order = newOrderByListClause(clauses...)
// return us
//}
//
//func (us *unionStatementImpl) Limit(limit int64) UnionStatement {
// us.limit = limit
// return us
//}
//
//func (us *unionStatementImpl) Offset(offset int64) UnionStatement {
// us.offset = offset
// return us
//}
//
//func (us *unionStatementImpl) String() (sql string, err error) {
// if len(us.selects) == 0 {
// return "", errors.Newf("Union statement must have at least one SELECT")
// }
//
// if len(us.selects) == 1 {
// return us.selects[0].String()
// }
//
// // Union statements in MySQL require that the same number of columns in each subquery
// var projections []Projection
//
// for _, statement := range us.selects {
// // do a type assertion to get at the underlying struct
// statementImpl, ok := statement.(*selectStatementImpl)
// if !ok {
// return "", errors.Newf(
// "Expected inner select statement to be of type " +
// "selectStatementImpl")
// }
//
// // check that for limit for statements with orderBy by clauses
// if statementImpl.orderBy != nil && statementImpl.limit < 0 {
// return "", errors.Newf(
// "All inner selects in Union statement must have LIMIT if " +
// "they have ORDER BY")
// }
//
// // check number of projections
// if projections == nil {
// projections = statementImpl.projections
// } else {
// if len(projections) != len(statementImpl.projections) {
// return "", errors.Newf(
// "All inner selects in Union statement must select the " +
// "same number of columns. For sanity, you probably " +
// "want to select the same tableName columns in the same " +
// "orderBy. If you are selecting on multiple tables, " +
// "use Null to pad to the right number of fields.")
// }
// }
// }
//
// buf := new(bytes.Buffer)
// for i, statement := range us.selects {
// if i != 0 {
// if us.unique {
// _, _ = buf.WriteString(" UNION ")
// } else {
// _, _ = buf.WriteString(" UNION ALL ")
// }
// }
// _, _ = buf.WriteString("(")
// selectSql, err := statement.String()
// if err != nil {
// return "", err
// }
// _, _ = buf.WriteString(selectSql)
// _, _ = buf.WriteString(")")
// }
//
// if us.where != nil {
// _, _ = buf.WriteString(" WHERE ")
// if err = us.where.Serialize(buf); err != nil {
// return
// }
// }
//
// if us.group != nil {
// _, _ = buf.WriteString(" GROUP BY ")
// if err = us.group.Serialize(buf); err != nil {
// return
// }
// }
//
// if us.order != nil {
// _, _ = buf.WriteString(" ORDER BY ")
// if err = us.order.Serialize(buf); err != nil {
// return
// }
// }
//
// if us.limit >= 0 {
// if us.offset >= 0 {
// _, _ = buf.WriteString(
// fmt.Sprintf(" LIMIT %d, %d", us.offset, us.limit))
// } else {
// _, _ = buf.WriteString(fmt.Sprintf(" LIMIT %d", us.limit))
// }
// }
// return buf.String(), nil
//}